FORCE

This is HEAVY!

I can’t hold it anymore!

Can someone help me?

FORCE• push or pull • object’s interaction with its

environment• vector quantity• unit is Newton

NET FORCE

• the sum of all the forces acting on the object.

• a physical quantity that is capable of changing an object’s state of motion

5 N

3 N

3 N

5 N

Net force = 2N, right

Net force = 8N, right

Four Fundamental Forces1. Gravitational Force

– Force of attraction between two masses

Position of the stars and planets

221

r

mmGFg

2. Electromagnetic ForceForce that affects charge particles

Your hair will be attracted to a charged balloon

The electrons from the clouds will travel towards the land - thunderbolts

3. Weak Nuclear Force

4. Strong Nuclear Force

Four Fundamental Forces

Radioactive decay

Binds proton in the nucleus

Forces acted on an object

1. Weight - gravitational attraction of an object and the earth- always directed downwards- W = mg weight

Normalforce

2. Normal Force- support force exerted upon an object- perpendicular to surface

Forces acted on an object

3. Applied force - force applied simply by pushing or pulling

weight

Normalforce

Appliedforce

Friction

4. Friction- force exerted by a surface as an object moves across it - parallel to surface and opposite to the direction of motion

Forces acted on an object

5. Tension - force which is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends.

Tension

6. Air resistance- force exerted by the air as an object moves in it- opposite to the direction of motion

Newton’s Law of Motion

Newton’s Law of Motion

1. Law of inertia

2. Law of Acceleration

3. Law of Interaction

I have answer to your inquiry

Law of InertiaThe body at rest tends to remain at rest, and a body in motion continues to move at constant velocity unless acted upon by a net force.

Inertia is the property of a body which resists any change in its state of rest or motion.

Inertia is proportional to mass.

Importance of using Seatbelts

Importance of Seatbelts

Seatbelt exerts force on the person for him not to move forward when it suddenly stops.

Force (seatbelt)

Try This at HomeEgg Drop Challenge

Law of Acceleration

The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object.

Law of Acceleration

Acceleration is directly proportional to mass

Acceleration is directly proportional to mass

a F

a 1/m

a = F/m

Law of Acceleration

maForm

Fa

Force (N) Mass (kg) Acceleration (m/s2) Your answer is...

20 ? 2 Try again

15 3 ? Try again

? 0.9 3 Try again

30 ? 0.5 Try again

0.6 0.2 ? Try again

? 20 10 Try again

Law of Interaction

For every action, there is an equal and opposite reaction.

Law of Interaction

You push the wall by 50 N

The wall push you by 50 N in the opposite direction

Action

Reaction

Law of InteractionAction Reaction

You push the ground downward

The apple is pulled by the Earth downward

The rocket exhausts gas to the ground downward

The ground will push you upward

The Earth is pulled by the apple upward

The gas will push the rocket upward